* {
    margin: 0;
    padding: 0;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}

html {
    width: 100%;
    font-family: '微软雅黑';
    font-size: 20px;
    outline: 0;
    -webkit-text-size-adjust: none;
}

body {
    width: 100%;
    margin: 0;
    padding: 0;
    -webkit-user-select: none;
}

.wrapper {
    background: url("img/xy_bg.jpg") top center no-repeat;
    background-size: 100%;
    width: 100%;
    height: 55rem;
    position: relative;
}

.top_btn {
    background: url("img/xy_btn.png") no-repeat;
    background-size: cover;
    width: 6.925rem;
    height: 2.475rem;
    position: absolute;
    top: 15rem;
    left: 0;
    bottom: 0;
    right: 0;
    margin: 0 auto;
}